CVE-2018-16869
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA Bleichenbacher type side-channel based padding oracle attack was found in the way nettle handles endian conversion of RSA decrypted PKCS#1 v1.5 data. An attacker who is able to run a process on the same physical core as the victim process, could use this flaw extract plaintext or in some cases downgrade any TLS connections to a vulnerable server.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA Bleichenbacher-type padding oracle vulnerability exists in nettle's RSA decryption code due to endian conversion timing side-channels in PKCS#1 v1.5 padding validation. An attacker running a process on the same physical core as the victim can exploit this to recover plaintext from RSA decrypted data or force TLS connection downgrades.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data<= 3.4CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Physical
- Complexity
- High
- Privileges
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify nettle library versionRun 'nettle-hash --version' or check the installed nettle library version via 'pkg-config --modversion nettle' or by examining /usr/lib/libnettle.so.* filesAffected if The installed nettle version is 3.4 or earlier
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Confirm nettle is used for RSA decryptionReview application dependencies and TLS server configurations to determine if nettle is linked for RSA operations; check process memory or library loading with 'ldd <binary>' or 'lsof -p <pid>' on running TLS servicesAffected if The system runs services or applications that use nettle for RSA decryption, such as TLS servers linking against libnettle
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Verify PKCS#1 v1.5 padding is in useInspect application configuration or code for RSA padding settings; check TLS cipher suites in use (RSA key exchange ciphers use PKCS#1 v1.5)Affected if The system accepts or requires RSA key exchange cipher suites or uses pkcs1_unpad functions from nettle for decrypted data processing
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Check for co-location attack surfaceReview multi-tenant environments or shared hosting where untrusted processes may share physical CPU cores with RSA decryption workloadsAffected if The environment hosts untrusted code on the same physical cores as processes performing RSA decryption with nettle
A system is affected if it runs nettle version 3.4 or earlier and performs RSA PKCS#1 v1.5 decryption operations, particularly in TLS contexts where an attacker could share a physical CPU core with the victim process.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpdate nettle to the patched version containing the fix; consider migrating from RSA PKCS#1 v1.5 to OAEP padding which is not vulnerable to Bleichenbacher-style attacks.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-16869 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2018-16869 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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